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Farhad S.,Carleton University | Yoo Y.,NRC Institute for Chemical Process and Environmental Technology | Hamdullahpur F.,University of Waterloo
Journal of Power Sources | Year: 2010

The performance of three solid oxide fuel cell (SOFC) systems, fuelled by biogas produced through anaerobic digestion (AD) process, for heat and electricity generation in wastewater treatment plants (WWTPs) is studied. Each system has a different fuel processing method to prevent carbon deposition over the anode catalyst under biogas fuelling. Anode gas recirculation (AGR), steam reforming (SR), and partial oxidation (POX) are the methods employed in systems I-III, respectively. A planar SOFC stack used in these systems is based on the anode-supported cells with Ni-YSZ anode, YSZ electrolyte and YSZ-LSM cathode, operated at 800 °C. A computer code has been developed for the simulation of the planar SOFC in cell, stack and system levels and applied for the performance prediction of the SOFC systems. The key operational parameters affecting the performance of the SOFC systems are identified. The effect of these parameters on the electrical and CHP efficiencies, the generated electricity and heat, the total exergy destruction, and the number of cells in SOFC stack of the systems are studied. The results show that among the SOFC systems investigated in this study, the AGR and SR fuel processor-based systems with electrical efficiency of 45.1% and 43%, respectively, are suitable to be applied in WWTPs. If the entire biogas produced in a WWTP is used in the AGR or SR fuel processor-based SOFC system, the electricity and heat required to operate the WWTP can be completely self-supplied and the extra electricity generated can be sold to the electrical grid. Crown Copyright © 2009.

Du N.,NRC Institute for Chemical Process and Environmental Technology | Park H.B.,Hanyang University | Robertson G.P.,NRC Institute for Chemical Process and Environmental Technology | Dal-Cin M.M.,NRC Institute for Chemical Process and Environmental Technology | And 4 more authors.
Nature Materials | Year: 2011

Microporous organic polymers (MOPs) are of potential significance for gas storage, gas separation and low-dielectric applications. Among many approaches for obtaining such materials, solution-processable MOPs derived from rigid and contorted macromolecular structures are promising because of their excellent mass transport and mass exchange capability. Here we show a class of amorphous MOP, prepared by [2+3] cycloaddition modification of a polymer containing an aromatic nitrile group with an azide compound, showing super-permeable characteristics and outstanding CO2 separation performance, even under polymer plasticization conditions such as CO2 /light gas mixtures. This unprecedented result arises from the introduction of tetrazole groups into highly microporous polymeric frameworks, leading to more favourable CO2 sorption with superior affinity in gas mixtures, and selective CO2 transport by presorbed CO2 molecules that limit access by other light gas molecules. This strategy provides a direction in the design of MOP membrane materials for economic CO2 capture processes. © 2011 Macmillan Publishers Limited. All rights reserved.

Kim D.S.,Sensors and Electrochemical Devices Group | Labouriau A.,Los Alamos National Laboratory | Guiver M.D.,NRC Institute for Chemical Process and Environmental Technology | Kim Y.S.,Sensors and Electrochemical Devices Group
Chemistry of Materials | Year: 2011

Guanidinium-functionalized poly(arylene ether sulfone) anion exchange polymer electrolytes were synthesized via activated fluorophnyl-amine reaction, followed by the methylation with dimethyl sulfate. The activated fluorine-amine reaction gives precise control of cation functionality without the deleterious side reactions and allows the direct connection of guanidinium into stable phenyl rings. © 2011 American Chemical Society.

Du N.,NRC Institute for Chemical Process and Environmental Technology | Park H.B.,Hanyang University | Dal-Cin M.M.,NRC Institute for Chemical Process and Environmental Technology | Guiver M.D.,NRC Institute for Chemical Process and Environmental Technology | Guiver M.D.,Hanyang University
Energy and Environmental Science | Year: 2012

Global CO2 emissions have increased steadily in tandem with the use of fossil fuels. A paradigm shift is needed in developing new ways by which energy is supplied and utilized, together with the mitigation of climate change through CO2 reduction technologies. There is an almost universal acceptance of the link between rising anthropogenic CO2 levels due to fossil fuel combustion and global warming accompanied by unpredictable climate change. Therefore, renewable energy, non-fossil fuels and CO2 capture and storage (CCS) must be deployed on a massive scale. CCS technologies provide a means for reducing greenhouse gas emissions, in addition to the current strategies of improving energy efficiency. Coal-fired power plants are among the main large-scale CO2 emitters, and capture of the CO2 emissions can be achieved with conventional technologies such as amine absorption. However, this energy-consuming process, calculated at approximately 30% of the power plant capacity, would result in unacceptable increases in power generation costs. Membrane processes offer a potentially viable energy-saving alternative for CO2 capture because they do not involve any phase transformation. However, typical gas separation membranes that are currently available have insufficiently high permeability to be able to process the massive volumes of flue gas, which would result in a high CO2 capture. Polymer membranes highly permeable to CO2 and having good selectivity should be developed for the membrane process to be viable. This perspective review summarizes recent noteworthy advances in polymeric materials having very high CO2 permeability and good CO2/N 2 selectivity that largely surpass the separation performance of conventional polymer materials. Five important classes of polymer membrane materials are highlighted: polyimides, thermally rearranged polymers (TRs), substituted polyacetylenes, polymers with intrinsic microporosity (PIM) and polyethers, which provide insights into polymer designs suitable for CO 2 separation from, for example, the post-combustion flue gases in coal-fired power plants. This journal is © 2012 The Royal Society of Chemistry.

Cozzolino A.F.,McMaster University | Whitfield P.S.,NRC Institute for Chemical Process and Environmental Technology | Vargas-Baca I.,McMaster University
Journal of the American Chemical Society | Year: 2010

The remarkable effect that secondary bonding interactions can have on the macroscopic properties of a material is illustrated by two polymorphs of the title compound. The phase which is most stable under ambient pressure and temperature consists of puckered supramolecular ribbon polymers assembled by Te - N secondary bonding interactions and displays a characteristic red-orange color. A second yellow phase consists of ribbons with alternating short and long intermolecular Te - N secondary bonding distances and is metastable; at 127 °C the material undergoes an exothermic irreversible transition to the red polymorph. A third phase consists of pyridine-solvated supramolecular dimers; it is also yellow and transforms into the red phase after the crystals effloresce. Computational DFT studies indicate that the observed changes in optical properties are related to intermolecular mixing of π orbitals enabled by the supramolecular interactions and the symmetry of the supramolecular synthon. © 2010 American Chemical Society.

Bensebaa F.,NRC Institute for Chemical Process and Environmental Technology
Progress in Photovoltaics: Research and Applications | Year: 2011

There are very few published data comparing performance and cost of thermal and photovoltaic (PV) based solar power generations. With recent intense technology and business developments there is a need to establish a comparison between these two solar energy options. We have developed a simple model to compare electricity cost using these two options without any additional fuel source of hybridization. Capital along with operation and maintenance (O&M) costs and other parameters from existing large scale solar farms are used to reflect actual project costs. To compete with traditional sources of power generation, solar technologies need to provide dispatchable electric power to respond to demand during peak hours. Different solutions for energy storage are available. In spite of their high capital cost, adding energy storage is considered a better long term solution than hybrid solar systems for large scale power plants. For this reason, a comparison between the two solar options is also provided that include energy storage. Although electricity storage is more expensive than thermal storage, PV power remains a competitive option. Expenses related to O&M in solar thermal plant are about ten times higher than PV, an important factor resulting in higher energy cost. Based on data from proven commercial technologies, this study showed that PV holds a slight advantage even when energy storage is included. © 2010 Crown in the right of Canada.

Liu F.,NRC Institute for Chemical Process and Environmental Technology | Smallwood G.J.,NRC Institute for Chemical Process and Environmental Technology
Applied Physics B: Lasers and Optics | Year: 2011

This study concerns the effect of soot-particle aggregation on the soot temperature derived from the signal ratio in two-color laser-induced incandescence measurements. The emissivity of aggregated fractal soot particles was calculated using both the commonly used Rayleigh-Debye-Gans fractal-aggregate theory and the generalized Mie-solution method in conjunction with numerically generated fractal aggregates of specified fractal parameters typical of flame-generated soot. The effect of aggregation on soot temperature was first evaluated for monodisperse aggregates of different sizes and for a lognormally distributed aggregate ensemble at given signal ratios between the two wavelengths. Numerical calculations were also conducted to account for the effect of aggregation on both laser heating and thermal emission at the two wavelengths for determining the effective soot temperature of polydisperse soot aggregates. The results show that the effect of aggregation on laser energy absorption is important at low fluences. The effect of aggregation on soot emissivity is relatively unimportant in LII applications to typical laminar diffusion flames at atmospheric pressure, but it can become more important in flames at high pressures due to larger primary particles and wider aggregate distributions associated with enhanced soot loading. © 2011 Her Majesty the Queen in Right of Canada.

Liu F.,NRC Institute for Chemical Process and Environmental Technology | Smallwood G.J.,NRC Institute for Chemical Process and Environmental Technology
Proceedings of the Combustion Institute | Year: 2011

Multi-port co-annular burners are widely used in practice to achieve low NOx and soot emissions from combustion devices. However, there is lack of fundamental studies on the structure and flame regime under different flow conditions. A conventional laminar axisymmetric coflow diffusion flame burner was modified by introducing a central air jet inside the fuel tube to investigate how the central air jet velocity affects the structure and sooting characteristics of a coflow methane/air diffusion flame. The modified burner produces a double flame structure: an inner inverse diffusion flame or an inner partially premixed flame and an outer normal diffusion flame. Experiments were conducted to observe the effect of the central air jet velocity on the appearance of the flame. At a given and relatively low central air jet flow rate the inner flame can be either a partially premixed one or an inverse diffusion one, depending on how the central air jet flow rate is adjusted. The overall flame structure and sooting characteristics can be controlled effectively by varying the flow rate of the central air jet. Detailed numerical calculations were conducted using GRI-Mech 3.0 without the NOx chemistry and a simplified soot model. Numerical results reproduce the experimental observations and provide detailed information on the flow field, temperature, and species concentration distributions. The central air jet is an effective aerodynamic means to control the flame size, structure, and sooting characteristics. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

Li Z.,NRC Institute for Chemical Process and Environmental Technology | Ding J.,NRC Institute for Chemical Process and Environmental Technology | Song N.,NRC Institute for Chemical Process and Environmental Technology | Lu J.,NRC Institute for Microstructural Sciences | Tao Y.,NRC Institute for Microstructural Sciences
Journal of the American Chemical Society | Year: 2010

A new s-tetrazine-based low-bandgap semiconducting polymer, PCPDTTTz, was designed and synthesized. This is the first solution-processable conjugated polymer with tetrazine in the main chain. This polymer shows good thermal stability and broad absorption covering 450-700 nm. The HOMO and LUMO energy levels were estimated to be-5.34 and-3.48 eV, with an electrochemical bandgap of 1.86 eV. Simple polymer solar cells based on PCPDTTTz and PC71BM exhibit a calibrated power conversion efficiency of 5.4%. © Published 2010 by the American Chemical Society.

Ding J.,NRC Institute for Chemical Process and Environmental Technology | Song N.,NRC Institute for Chemical Process and Environmental Technology | Li Z.,NRC Institute for Chemical Process and Environmental Technology
Chemical Communications | Year: 2010

A new copolymer of dithienosilole (DTS) and dithienyl-s-tetrazine (TTz), PDTSTTz, has been designed and synthesized. This solution processable polymer shows a low band gap, strong absorption and good thermal stability. Solar cells from the blend of this polymer with PC71BM showed power conversion efficiency (PCE) up to 4.2%. © 2010 The Royal Society of Chemistry.

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